424 Greenpower

The first-ever PERRINN 424 car to race in real life

We are building a small PERRINN 424 electric racing car that will compete in the UK Greenpower Championship

🎧During the events, stay close to the action by listening to our team radio live!🎧

Download the "Zello Walkie Talkie" app on your smartphone:

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Search for the "PERRINN 424 Greenpower" channel in the app or scan the QR code:

▶️PERRINN 424 Greenpower radio

Listen to the 424 radio!

Live timing

Follow timing of 424 live during tests and races from the Speedhive website or mobile app.
https://speedhive.mylaps.com/
Search for Greenpower in United Kingdom to find the event you want to follow.

The challenge

The 424 Greenpower prototype (nicknamed "baby 424") is going to take part in the UK Greenpower Championship from 2026 onwards.

This competition aims at inspiring young engineers to excel in Science, Technology, Engineering and Maths. A leitmotiv that meets one of PERRINN's pillars as we make a point of making Motorsport more accessible and creating new opportunities for talents from around the world.

Our approach

To enter the races, we are partnering with an already established team of young people : Chainreaction, based near Bristol (UK). The car will compete in both the Formula 24 ("F24") and the Formula 24+ ("F24+") categories. The difference lies in the age of the participants and the race lengths.

Of course we remain true to our open source philosophy. All data and information is shared with our community & followers. Other teams even have the possibility to use the design of our prototype as it is completely accessible.

Our goal is to prove its potential by hopefully winning the championship.

An open-source and transparent project, conceived to show what's possible when engineering becomes accessible

Design phase

More than 200 hours spent designing 424 Greenpower car, completing CFD & stress analysis as well as setting out the bill of material.

Aerodynamic optimisation

More than 55 tests on Bramble CFD to reduce drag as much as possible.

Numerous paths have been explored to optimize aero efficiency and reach a drag coefficient (SCx) of less than 0.065: refined upper- and underside chassis shapes, front & rear skirts, wheel arches, pointy/narrower/lower nose (for less front wheel wake), lower/longer chassis, lower/shorter/longer tail,...

Stress-checked structures

Lightweight design is of course the way to go...while not jeopardizing overall stiffness.

Stress analysis of the chassis has been completed to find the right compromise. Every aspect was optimized to get the lightest prototype possible: chassis thickness, protective foam volume, metal parts design, material selection...

CAD data is open access in Onshape!

Every component drafted in detail

Chassis, steering wheel, tires, battery packs & lid, bodywork, windscreen, adjustable mirrors, roll hoop, motor tray, camera housing, transponder location, helmet fairing, locating & quick release pins, mounting holes, chain transmission & tension mechanism as well as platewheel & pinions (8 gear ratios in total), uprights, seatbelts, master switch & horn integration, floating anchor nuts, double nuts, bolts, wheel hub & spokes, etc... all parts have been carefully detailed so that the 424 Greenpower prototype does not remain a virtual concept. Even the livery has been adapted to help with applying to the real car!

Designed to inspire young engineers

Manufacturing phase

The car was assembled by the Chainreaction race team.

Every component has been designed with technical feasibility in mind :

Composite parts - chassis & bodywork components like sidepods, rear wheel fairing, tail, nose, rear cover and roll hoop cover,...
Metal parts (mainly aluminium 6061) - roll hoop, motor tray, wheels, steering components, uprights, caliper brackets,...
3D printed parts - steering wheel, headrest, battery packs, mirrors,...

All parts were manufactured by April 2026, which allowed us to be ready for the season opener. We have agreed on partnerships with 5 companies that have supported us during this important phase of the project. The total cost of the car has more than halved thanks to them:

FLEX3D - 3D printed parts
KOMACUT - Metal parts (cut)
REVOZPORT - Composite parts
SOLFINITE TECHNOLOGY & DRIVETRAIN DEVELOPMENTS - Metal parts (CNC)

In addition to these bespoke components, a range of off-the-shelf articles were used like mountain bike hydraulic brakes, batteries, electric motors, speed controllers, a micro switch, mirrors and even a radio & telemetry system. The latter is based on an open source software connected to a smartphone directly fixed to the steering wheel so that data are diplayed to the driver.

Chainreaction team's previous car weighed approximately 75 kg. Baby 424 weight is around 66 kg which is comparable to the top team's prototypes. Some ideas to reduce it even further are already in our mind and could lead to some updates ahead of the following season.

Design adjustments & production tools

Manufacturing

3D printed parts weight & cost

Metal parts weight: predicted vs. actual

Baby 424 assembly and battery testing

A specific workbench has been built with a wood sheet, foam and tressels. It will be used in the team's workshop, in the paddock during competitions and for transport as well. Indeed, a trailer was bought and fitted out to carry baby 424.

In parallel, the batteries have been tested and the telemetry & radio systems set up.

The assembly of baby 424 was carried out in several phases:

metal components and 3D printed parts were pre-assembled
8 wheels were built (4 + 4 spare)

the wiring loom of the motor, the speed controller, the wheel speed & temperature sensors, as well as the busbars were installed
the steering wheel, telemetry system and brakes have needed special tuning
subassemblies were fitted to the carbon chassis
the cockpit & driver seat were prepared with foam bonding

Let's go racing !

At each venue, races are organised for 2 different classes:

”Formula 24” → A category for 11- to 16-year-olds. There are two 90-minute F24 races per event. For each race, at least 3 drivers share driving duties. The winner is the car that goes the furthest distance on a single battery charge.
”Formula 24+” → A category for 16- to 25-year-olds. The race is 60 minutes long and only 1 driver is required. The winner is the car that goes the furthest distance on a single battery charge.

We are registered to participate in 6 events throughout the year. If our results meet the expectations, you may also see us at the international finals in Goodwood at the end of the season.

As far as we are concerned, the plan is to focus on F24+ races in the 4 first rounds of the season, before the summer break. Then, we intend to enter F24 races as well in the next 2 rounds but for that we need to train additional drivers and practice driver change. We will also organise a test ahead of the Castle Comb event on this same track which is ideal for preparing the race.

SHAKEDOWN

Baby 424 assembly was finalized at the very end of April 2026, leaving very little room for testing. In spite of this tight timeline, we were able to complete a 20 km shakedown some days prior to the first heat of the season. This enabled us to bleed the brakes and sort a couple of wiring issues.

#1 Mallory Park Heat - 6th May 2026

At Mallory Park, the day started with a practice session where we tested 2 drivers and 2 gear ratios: we switched from 2.82 to 2.67, which proved to be a step in the right direction.

Building on that, we took part in the F24+ race in the afternoon and finished P2, 10 seconds off the winner. Baby 424 showed great pace and reliability which is very positive as we now have a strong platform to keep improving.